The present invention relates to a method for determining the winder quality of a film roll of a film on a winder roller and a monitoring device for monitoring the winder quality of a film roll of a film on a winder roller.
It is basically known that films are wound up subsequent to their production. The winding up occurs normally to a winder roller so that a so called film roll results on the winder roller. During the winding on certain parameter are essential. Thus, a winding on often occurs with inclusions of an air gap between the layers. Between the single layers of the film on the film roller air is inserted during the winding on so that an air gap or an air cushion develops between the single layers of the film in the film roll. The thickness of this air cushion influences the flexibility and therewith the softness of the whole film roller. This flexibility can also be described as winder quality. Particularly, this winder quality is crucial for the downstream further processing as for example the winding up of the film roll for the further processing. The further processing can for example be the printing of the film or the filling of for example a tubular bag. Thereby, particularly a defined winder quality is an advantage, which is determined within certain limits, thus above or below of standard values in a standard area.
It has already been proposed that the winder quality is monitored. For monitoring the winder quality basically two parameters from the state of the art are known. On the one hand it is known that the winder density is monitored, this occurs normally by a calculation or a counting of the running winding on process. Such a method is for example described in DE 41 16 081 A1. Disadvantageously with this determination of the winder density however a high calculative regulation effort and the plurality of different operating parameters, which have to be continuously monitored is necessary. From this indirect calculation of the winder thickness overall a higher inaccuracy occurs by the determination of the winder quality. Beneath the winder thickness it is also known that the roll hardness makes a statement about the winder quality of the film roller. It has been for example explained in DE 83 10 005 that the roll hardness can be determined as a dimension for the winder quality. A disadvantage with the previous determination of the roll hardness is however that this can only be performed subsequent to the termination of the winding on process. In this described DE 83 10 005 herefore a plurality of paper tapes is also wound on during the winding on process. After termination of the winding on process a conclusion to the roll hardness can be made by the measurement of the force during the extraction of these single paper tapes. At this point of time however the winding on process is already completed. Possibly, too strong or too soft winding on and accordingly a poor winder quality beyond the standard values is therewith only recognized at a point of time at which no regulation or intervention in the winding on is possible. This winder accordingly comprises a bad quality and can only be delivered with reduced prices or not at all with the further processing.
Beneath the reversion of the film wrap also the sum profile regulation for film rolls is known from DE 36 31 503 in order to generate an even winder quality over the width of the film roll. The therein described regulation however does not respect the compensatory characteristics of the air film between the film layers so that the film profile is unnecessarily strong influenced.